com interop - Marshal.GetActiveObject() throws MK_E_UNAVAILABLE exception in C#

Question

The following vbscript code works prefectly fine:

Dim App 
Set App = GetObject("","QuickTest.Application")
App.Quit

But when I translate it into C# code as below:

class Program
{
    [STAThread]
    static void Main(string[] args)
    {
        object qtApp = Marshal.GetActiveObject("QuickTest.Application");
        (qtApp as QuickTest.Application).Quit();
    }
}

I get the exception:

An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll

Additional information: (Exception from HRESULT: 0x800401E3 (MK_E_UNAVAILABLE))

I don't think the problem is related to ROT, because the vbscript code works. So what is wrong with the C# code?

Answer 1

I found that running the debugger/IDE with elevated privileges (i.e. Admin mode) can cause this problem when the process you are trying to detect is running without elevated privileges.